just out of curiosity, why do you want to vape dry herb? I remember when vapes first came out for this, I never got even a buzz off of those things. They just didn't work very well, imo. I tried both the Volcano and one that was made in Colorado called THeCan. Wasn't even remotely happy with either of them, ended up selling them or giving them away..
I don't believe a coil in a pen is the best way to go either. I don't believe you would get adequate heat to proportionally evaporate the herb, and would end up burning it, to boot. I could be wrong, depending on your rig, it might work.
Personally if I were into vaping like that, I would buy a hydraulic press from harbor freight and a live rosin heat plate and press it straight out of the nugs. Then put it in a pen. I guess that would be more work and probably cost more than you're willing to spend?
Just asking. I just really thought those dry herb vaping machines were a waste of time and money and didn't get me or any of my friends high. Good way to turn your weed brown real fast, though. Lol. Different strokes for different folks!
Edited to say - oops, I missed you said e-nail. Which isn't a whole lot different from a pen, but yeah same question applies?